Steel is used practically in all structural formations of buildings raging from all sizes (e.g., house, apartment buildings, office buildings, sky-rises, etc.). When developing such structures, one must be aware of the buildings strength and resistance to heat in the case of a fire. Steel has very unique physical properties in that it has a melting point of about 3,300° F.; however the framework of steel tends to change when susceptible to temperatures of 800° F.-1,200° F. At these temperature ranges, steel tends to twist in a number of directions, sag and most importantly lose most of its structural strength. To be more specific, steel tends to lose about 20% of its design strength at 800° F. Moreover, at 1,200° F., a temperature easily reached in a fire, the steel will lose up to 70% or more of its design strength.
Protecting structural steel from the heat of a fire can be achieved in a plurality of ways. First, the steel can be encased in concrete or substituted masonry materials (e.g., brick, stone, marble, granite, travertine, limestone, cast stone, glass block, stucco, tile, etc.). Unfortunately masonry construction tends to be a slow, expensive process and such materials tend to produce significant weight concerns. Secondly, there are sprinkler systems available, “deluge systems”, which supply water over and around the steel members so that heat from a fire never has the opportunity to affect the strength of the protected member. Although the deluge system presents itself as the most effective manner in which to protect the structural integrity of steel, the deluge system creates tremendous water supply and runoff difficulties.
Sprinklers add water, which absorbs heat and tends to control the availability of oxygen, thereby controlling the fire's size and intensity. Compartmentalization (e.g., firestopping) is designed to keep the fire from spreading, from area to area and floor to floor. Structural preservation is the primary design function of spray-applied fire resistant materials.
Spray applied fireproofing is designed to preserve the structural integrity of the “assembly” that it seeks to protect by keeping the substrate, usually steel, at temperatures that are relatively cool (e.g., 350° F. range). This is significantly different from the design intent of active sprinkler systems. Sprinkler systems rely on a water distribution system usually comprised of heavy-duty pipes connected in a rigid system. Head of wall firestopping has a design deflection capability of approximately ¾ of an inch. Obviously, without structural stability both the compartmentalization and the sprinkler systems will fail, which is why the argument for redundancy and balanced fire safety systems is so compelling.
Spray fireproofing consists of a process in which a fire resistant material (e.g., plaster-like materials) is sprayed on steel surfaces. The fire resistive material is designed to keep elevated temperatures away from the steel substrate by converting the captured water within the material to steam, over a specified period of time (e.g., 1 to 4 hours). Supplementing this basic water conversion process compliments additional reactions that contribute to this time delay including for example, reflection or deflection, absorption, self-combustion, and other endothermic reactions. However, for any of them to work the fire resistive material must be applied correctly.
The present invention has been verified by 3 nationally recognized laboratories: 1) VTEC; 2) Intertek; and 3) Underwriters Laboratories. The present invention has passed ASTM E 84 for flame spread and smoke developed, the ASTM E 119 for retention of structural integrity, and the ASTM E 119/UL 263 for thermal resistivity of at least 2 hours.
Underwriters Laboratories (hereinafter referred to as “UL”) previously required fireproofing patches to be formulated out of the same materials used in the initial fireproofing coating process. UL additionally requires that the applicator of the fireproofing patch be certified in such field. What is unique about the present invention is that it teaches away from all art that has been previously disclosed while conforming to all UL guidelines at the same time.
The judicious evaluation of fire protective designs and technologies determine the potential for structural collapse, the risk assessment to human life, and the economic liabilities that would be created in the event of a fire.
U.S. Pat. No. 6,746,533 of Ksionzyk discloses a method for increasing the drying rate of set plaster to form fireproofing material consisting essentially of hydrated calcium sulfate hemihydrates, and the method consisting essentially of adding to a drying accelerant to the setting plaster. Additionally, U.S. Pat. No. 5,034,160 of Kindt; U.S. Pat. No. 6,309,740 of Shu et al.; and U.S. Pat. No. 5,556,578 of Berneburg discloses a sprayable cementitious fireproofing composition, however, these references in their entirety and in combination with one another fail to disclose the novel features of the Universal Fireproofing Patch.
Existing methods are labor-intensive and expensive. It would be advantageous to provide a universal patch system that can be used when the existing material is either unknown or unavailable and methods for fireproofing walls, ceilings or floors that require less labor and materials than presently existing methods.